Device for use with slings, particularly bag slings for use in unit loading



Jan. 9, 1968 B. A. A. EK 3,362,744

DEVICE FOR USE WITH 5 GS, PARTICULARLY BAG LIN SLINGS FOR U IN UNITLOADING Filed Feb. 4, 1966 INVENTOR BYh/M United States Patent Office3,362,744 Patented Jan. 9, 196$ ABSTRACT OF THE DISCLOSURE The inventionis a buckle for slings wherein a selflocking catch is provided whichwhen in locking position is contained within the contour line of thebuckle. Means are provided for easily releasing the self-locking catchand to hold it in such released position.

This invention relates to a device at slings particularly so-called bagslings intended for use in unit loading, i.e. slings which aremaintained on the load from application until the load has reached itsdestination and which, if needed, can be used during transport forre-stowage. Slings of this type comprise a strap, provided at one endwith a suspension loop and at the other end with a locking deviceconsisting of a metal buckle through which passes the loop end of thestrap.

In the loading of bags and the like with the aid of such slings it isimportant that the sling is maintained securely around the load when thelifting force is diminished or completely interrupted and that it isfurther tightened at any new lifting action, so as to prevent the loadfrom falling free of the sling. It is likewise important that the slingcan be easily released from the load when desired. Furthermore, it isimportant that no sharp or pointed details project from the lockingdevice, since they might cause damage to the load unitsoften ofconsiderable weightwhen these units are placed on top of each other, andthus also on top of a locking buckle. If the projecting details areparts constituting the very locking mechanism of the sling, thismechanism might be released by any load placed on top of it therebyloosening the grip of the strap around the load.

The object of the present invention is to provide a sling in which allthese requirements are fulfilled, viz. a sling which has anautomatically tightening grip around the load at lifting action, whichdoes not slide off the load at depositing thereof, and which can beeasily released from the load whenever desired. To bring about theseadvantages the device according to the invention is characterised by aspring loaded locking lever arranged to press the strap traveling in themetal buckle into firmly gripping engagement with said buckle at a pointsituated a minor distance above the line connecting the central point ofthe locking lever axis with the central point of that part of the metalbuckle with which the locking lever is arranged to engage in the lockingposition, the locking lever and its spring being arranged in such a waythat in the locking position they are contained within the contour linesof the metal buckle.

The invention will be described in detail in the following withreference to the accompanying drawing in which:

FIG. 1 shows the sling according to the invention, encircling a load,

FIG. 2 is a fragmentary plan view of the locking device for the sling,with some parts broken away, and

FIG. 3 is a section of the sling as illustrated in FIG. 2.

As shown in FIG. 1 the sling according to the invention consists of astrap 1 arranged to be wrapped around the load 2. At one of its ends,the strap 1 has a loop 3 by means of which the strap is suspended in alifting hook 4 of a hoisting crane, not shown. At its opposite end, thestrap 1 is provided with a locking device 5 arranged to be passed aroundthe loop end 3 of the strap when the sling has been placed around theload 2.

As shown in FIGS. 2 and 3, the locking device 5 consists of arectangular metal buckle 6 which, according to the illustratedmodification, comprises two side parts 7 and 8 interconnected throughtransverse metal pins 9 and 10. A locking lever 13, operated by a spring12, is journalled about an axis 11 arranged between the pins 9 and 1t)and parallel thereto, one end 14 of the locking lever 13 being urged bythe spring 12 to engage with the pin 10 at a point situated, as can beseen in FIG. 3, somewhat above an imaginary line interconnecting thecentral points of the pins 9 and 10.

The attachment of the sling around the load takes place in the followingmanner. The loop end 3 of the strap is inserted from underneath (withrelation to FIG. 3) between the end 14 of the locking lever 13 and themetal pin 10, and the strap 1 can then be tightened around the load 2usually consisting of one or more bags, so that upon pulling movement ofthe strap 1 in this direction the locking lever 13 is turned upwardsagainst the action of the spring 12, the end 14 of the lever swinginginto its upper, releasing position. This upward movement of the lever 13thus occurs when the load is being lifted, the angle or automaticallyadjusting itself to 120.

When the load is being deposited it will exert a pulling action on thestrap 1 in the opposite direction but the friction between the strap 1and the lever 13 together with the action of the spring 12 urge thelocking lever end 14 to securely press the strap 1 against thetransverse pin it) so that the sling stays looped around the load to beused at the next hoisting, for example at stowing or unloading.

To release the sling from the load, the operator presses with a fingeron that end 15 of the locking lever 13 which is opposite the end 14thereof so that this latter end is swung upwards, releasing the strap 1.To facilitate the swinging movement of the locking lever 13 a lever 17(FIG. 3) is journalled about an axis 16, one end 18 of said lever 17exerting pressure on the locking lever end 15 so as to swing itdownwards (with relation to FIG. 3) whereby the strap 1 is released.

In this connection it should be noted that considerable powers arebrought into play at the locking of the sling, and the lever 17 as shownin FIG. 3 has in practice proved insufficient to counteract the lockingforce of the locking lever 13. It has therefore been necessary toprovide the lever 17, at the end 18 thereof, with a shoulder projectingfrom the underside of the lever 17 in order to improve the lever action,i.e. to reduce the distance between the axis 16 and the point of contactof the lever with the locking lever 13. This simple modification hasproved sufiicient to ensure an easy release of the locking device. Someconsiderable concentration of force is needed to do away with the wedgeeffect, as obtained and to give an example thereof it should bementioned that in the case of a sling, having a thickness ofapproximately 5 mm. and used to lift a cargo loading the sling with1000-1 kilos, the sling is extended to such a degree that its thicknessis approximately 2.5 mm. When the lifting action is completed and thesling unloaded, a locking intensity of 200-300 kilos is obtained. It isreadily understood that considerable power is required to nullify alocking intensity of this kind and, in order that separate tools bedispensed with, special steps must be taken, as in the device accordingto the invention.

The invention is not limited to the embodiment as illustrated in thedrawing and described in the foregoing but several modifications thereofare possible Within the scope of the appended claims. The axis 11, forinstance, might have such cross section as to enable it to cooperatewith the blades forming the locking lever 13, thus providing the springaction required to secure the strap 1 against the pin 10. Therectangular metal buckle 6 can be shaped in many difierent ways.Furthermore, the lever 17 might be spring actuated to assist in pressingthe locking lever end 14 against the pin it).

What I claim is:

1. A sling arrangement, particularly bag slings comprising a straphaving one suspension loop end and one locking device end, a lockingdevice comprising a metal buckle to be passed over said suspension loopend of said strap, a locking lever pivotally mounted in said buckle, aspring urging said lever to press said strap running in said metalbuckle into gripping engagement with said metal buckle at a pointsituated a short distance above the line connecting the central point ofthe axis of said locking lever with the central point of the metalbuckle part with which said locking lever is arranged to engage in thelocking position, said locking lever and said spring when in lockingposition being located within the contour lines of said metal buckle anda pivoted lever is located within said buckle adjacent said lockinglever to force said locking lever out of gripping engagement with saidstrap.

2. A sling arrangement as set forth in claim 1 wherein said last namedlever is spring loaded,

3. A sling arrangement as set forth in claim 1 wherein a spring lever isprovided pivotally mounted in said buckle to force said locking leverout of gripping engagement with said strap.

4. A sling arrangement as set forth in claim 1 wherein two spring leavesform said locking lever, an axis arranged for cooperation with said twospring leaves and designed in a manner corresponding to said springleaves, in order to bring about the swinging movement of said lockinglever into locking position and a lever is provided to force saidlocking lever out of gripping engagement with said strap.

5. A spring arrangement as set forth in claim 4 wherein said last namedlever is spring loaded.

References Cited UNlTED STATES PATENTS 292,934 2/1884 Menzel 24134416,985 12/1889 Beattie 24-170 FOREIGN PATENTS 329,439 5/ 1930 GreatBritain.

GERALD M. FORLENZA, Primary Examiner.

G. F. ABRAHAM, Assistant Examiner.

